Listeriosis is a rare infection caused by the bacteria called listeria. In most cases it causes a fever, aches and pains, vomiting and diarrhoea but in vulnerable people, such as the elderly, it can be fatal.

Dr Lisa Ackerley, aka the Hygiene Doctor, said the most important thing to stop the bacteria breeding in your freezer is to wrap food up in bags as tight as possible - to ensure all the air is squeezed out.

4. Bread

Bread can be defrosted one slice at a time or a whole loaf at a time, but don't defrost in the fridge as this will make it stale

Storing bread in the freezer is a great way to stop it from going off quickly - and you can take out a slice at a time as you need it, or the whole loaf.

But the same rules apply - wrap it tightly to avoid bacteria contamination and freezer burn.

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Listeriosis is a rare infection caused by bacteria called listeria.

It usually goes away on its own, but can cause serious problems if you're pregnant or have a weak immune system.

Symptoms:

In most people it only causes mild symptoms for a few days, including:

a high temperature of 38C or above

aches and pains

chills

feeling sick or vomiting

diarrhoea

But in vulnerable people, including the elderly, those with existing conditions like diabetes and pregnant women, listeriosis can cause serious problems.

People with vulnerable immune systems are more at risk of the bug attacking their immune system.

They may become seriously ill for longer than a few days and in the worst case scenario the bug may result in death.

"Wrap well and keep away from meat and poultry," Lisa said.

"Take out one slice at a time for toast and toast it, it saves waste.

"If you want the whole loaf take it out and defrost at room temperature as bread goes stale in the fridge.

"If you are making sandwiches you can make them with frozen bread slices and they will defrost slowly and keep fresh in a lunch box, but use an ice pack as well to keep the filling safe if it is likely to support bacteria growth - like cooked meat, eggs, soft cheese, fish and salads.

"Jam, Marmite and peanut butter are fine."

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5. Dairy products

Most pre-frozen dairy products are designed to be eaten frozen, but some milks and yoghurts can be bought frozen to be eaten defrosted.

Plus, you may want to freeze fresh bought milk or other products to stop it going off too soon.

"Keep it away from raw meat and poultry and wrap tightly," Lisa said.

"Follow instructions for defrosting and use, but generally you will need to defrost in the fridge."

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